Many machines utilize implement systems to move a payload from one location to another. The implement systems often include one or more hydraulic cylinders to cause the movement of the implement system. Payload control or estimation systems have been developed to measure the payload being carried by the implement system. Some payload estimation systems utilize forces measured at one or more of the hydraulic cylinders as part of the payload estimation system.
The force measured at a hydraulic cylinder may not accurately reflect the load on the hydraulic cylinder due to friction of the cylinder. The friction associated with the hydraulic cylinder is generally composed of three components, namely Coulomb friction, viscous friction, and friction from the seals within the hydraulic cylinder. The friction of the seals of a hydraulic cylinder generally varies with the pressure of the hydraulic cylinder.
U.S. Pat. No. 3,717,025 discloses a method of determining static and dynamic coefficients of friction by using a testing apparatus. The apparatus uses a pivoting disc and equating the static and dynamic coefficients of friction to a torque read-out based upon the pivoting disk.
The foregoing background discussion is intended solely to aid the reader. It is not intended to limit the innovations described herein, nor to limit or expand the prior art discussed. Thus, the foregoing discussion should not be taken to indicate that any particular element of a prior system is unsuitable for use with the innovations described herein, nor is it intended to indicate that any element is essential in implementing the innovations described herein. The implementations and application of the innovations described herein are defined by the appended claims.